Process control system for automated continuous production of chewing gum

ABSTRACT

A system is provided for automatically and continuously producing chewing gum and/or chewing gum base. A system controller receives inputs of parameters necessary for production. Ingredients are automatically and continuously fed and mixed to form a desired end product. During production of chewing gum, the gum is automatically and continuously discharged from the mixer and can be automatically dusted, rolled, scored and wrapped. The system is continuously monitored with appropriate sensing devices. Signals indicative of the sensed conditions are sent to the controller, and the system automatically adjusts to produce a consistent end product. An alarm is activated upon sensing of a predetermined condition.

FIELD OF THE INVENTION

The present invention is a process control system and a method forautomated continuous production of chewing gum.

BACKGROUND OF THE INVENTION

Conventionally, chewing gum base and chewing gum product have beenmanufactured using separate mixers, different mixing technologies and,often, at different factories. One reason for this is that the optimumconditions for manufacturing gum base, and for manufacturing chewing gumfrom gum base and other ingredients such as sweeteners and flavors, areso different that it has been impractical to integrate both tasks.Chewing gum base manufacture, on the one hand, involves the dispersive(often high shear) mixing of difficult-to-blend ingredients such aselastomer, filler, elastomer plasticizer, base softeners/emulsifiersand, sometimes wax, and typically requires long mixing times. Chewinggum product manufacture, on the other hand, involves combining the gumbase with other ingredients such as product softeners, bulk sweeteners,high intensity sweeteners and flavoring agents using distributive(generally lower shear) mixing, for shorter periods.

In order to improve the efficiency of gum base and gum productmanufacture, there has been a trend toward the continuous manufacture ofchewing gum bases and products. U.S. Pat. No. 3,995,064, issued toEhrgott et al., discloses the continuous manufacture of gum base using asequence of mixers or a single variable mixer. U.S. Pat. No. 4,459,311,issued to DeTora et al., also discloses the continuous manufacture ofgum base using a sequence of mixers. Other continuous gum basemanufacturing processes are disclosed in European Publication No.0,273,809 (General Foods France) and in French Publication No. 2,635,441(General Foods France).

U.S. Pat. No. 5,045,325, issued to Lesko et al., and U.S. Pat. No.4,555,407, issued to Kramer et al., disclose processes for thecontinuous production of chewing gum products. In each case, however,the gum base is initially prepared separately and is simply added intothe process. U.S. Pat. No. 4,968,511, issued to D'Amelia et al.,discloses a chewing gum product containing certain vinyl polymers whichcan be produced in a direct one-step process not requiring separatemanufacture of gum base. However, D'Amelia et al. focus on batch mixingprocesses not having the efficiency and product consistency achievedwith continuous mixing. Also, the single-step processes are limited tochewing gums containing unconventional bases which lack elastomers andother critical ingredients.

In order to simplify and minimize the cost of chewing gum manufacture,there is a need or a desire in the chewing gum industry for anintegrated continuous manufacturing process having the ability tocombine chewing gum base ingredients and other chewing gum ingredientsin a single mixer, which can be used to manufacture a wide variety ofchewing gums. Furthermore, there is a need to perform the production ofchewing gum and/or chewing gum base in not only a continuous fashion,but automatically, with minimal or no human intervention.

SUMMARY OF THE INVENTION

The present invention is a process control system and method for theautomated continuous production of a wide variety of chewing gumproducts. The present invention may use a single high efficiency mixerwhich does not require the separate manufacture of chewing gum base.

To this end, in an embodiment, a system is provided for the automaticand continuous production of chewing gum. The system has means forinputting operational parameters; means for automatically feedingingredients necessary for continuous production of chewing gum; meansfor collecting and automatically and continuously mixing theingredients; and means for controlling the means for automaticallyfeeding and the means for automatically and continuously mixing by inputof the operational parameters to the means for controlling.

In an embodiment, means is provided for monitoring ingredienttemperatures and providing a signal indicative thereof to the means forcontrolling.

In an embodiment, means is provided for monitoring feed rate of theingredients fed by the means for automatically feeding and providing asignal indicative thereof to the means for controlling.

In an embodiment, means for automatically forming the mixed ingredientsinto a predetermined shape discharged from the means for collecting andautomatically and continuously mixing is also provided.

In an embodiment, means is provided for automatically dusting thepredetermined shape formed in the means for automatically forming.

In an embodiment, means for automatically scoring the predeterminedshape is provided.

In an embodiment, means for automatically wrapping the predeterminedshape following division thereof into defined units is provided.

In another embodiment, a system is provided for automatic and continuousproduction of chewing gum base. The systems comprises: means forinputting operational parameters; means for automatically andcontinuously feeding ingredients necessary for continuous production ofchewing gum base; means for collecting and automatically andcontinuously mixing the ingredients; and means for controlling the meansfor automatically and continuously feeding and the means forautomatically and continuously mixing by input of the operationalparameters to the means for controlling.

In another embodiment of the present invention, a method is provided forautomatically and continuously producing chewing gum. The methodcomprises the steps of: inputting operational parameters; automaticallyand continuously feeding ingredients into a mixer wherein theingredients are necessary for continuous production of chewing gum;automatically and continuously mixing the ingredients in the mixer; andcontrolling the automatic and continuous feeding and mixing based on theoperational parameters.

In an embodiment, the method further comprises the steps of: monitoringproperties of the ingredients; and providing a signal indicative of theproperties.

In an embodiment, the method further comprises the step of providing analarm to signal an error condition during production of the chewing gum.

In an embodiment, the method further comprises the steps of: monitoringfeed rate of the ingredients fed during production; and providing asignal indicative of the feed rate.

In an embodiment, the method further comprises the step of displayingthe operational parameters continuously and in real time duringproduction.

In an embodiment, the method further comprises the steps of:continuously discharging the mixed ingredients; and automaticallyforming the mixed ingredients into a predetermined shape.

In an embodiment, the method further comprises the step of automaticallywrapping the predetermined shape following division into a plurality ofdefined units.

In yet another embodiment of the present invention, a system is providedfor automatic and continuous production of chewing gum. The system hasmeans for automatically and continuously feeding ingredients necessaryfor continuously producing the chewing gum; means for continuouslymixing the ingredients to form a mixture; means for automatically andcontinuously discharging the mixture from the means for mixing; meansfor automatically forming the mixture into a predetermined shape; meansfor automatically scoring the predetermined shape; and means forautomatically wrapping the predetermined shape following division into aplurality of defined units.

In an embodiment, the system further comprises means for inputtingoperational parameters and controller means receiving the operationalparameters and controlling the system based on the operationalparameters.

In an embodiment, the system further comprises means for monitoring theingredients and mixture during feeding and mixing.

In an embodiment, the system further comprises means for monitoring themixture during forming, scoring and wrapping.

In an embodiment, the system further comprises an alarm means providinga signal indicative of a condition sensed during the production.

In another embodiment of the present invention, a method forautomatically and continuously producing chewing gum is provided. Themethod comprises the steps of: feeding ingredients into a continuousmixer; mixing the ingredients in the continuous mixer to form a mixture;discharging the mixture from the container; automatically forming themixture into a predetermined shape; scoring the predetermined shape todefine units; and automatically and continuously wrapping thepredetermined shape following division into defined units.

In an embodiment, the method comprises the step of dusting thepredetermined shape with a substance.

In an embodiment, the method comprises the step of inputting operationalparameters necessary for producing the chewing gum.

In an embodiment, the method comprises the step of sensing properties ofthe ingredients and the mixture during production.

In an embodiment, the method comprises the step of controllingproduction based on the sensed properties.

In an embodiment, the method comprises the steps of sensing propertiesof the ingredients and the mixture during production and comparing thesensed properties with the operational parameters.

In an embodiment, the method comprises the step of controllingproduction of the chewing gum based on the comparison.

In an embodiment, the method comprises the step of providing an alarmindicative of a predetermined condition detected during production.

In an embodiment, the method comprises the step of displayingcontinuously and in real time status of production and other operationalparameters.

With the foregoing in mind, it is a feature and advantage of theinvention to provide an automated continuous system and method formanufacturing chewing gum.

It is also a feature and advantage of the invention to provide anautomated continuous system and method for making chewing gum whichrequires less labor than conventional manufacturing methods.

It is also a feature and advantage of the invention to provide anautomated continuous system and method for producing chewing gum havinggreater product consistency, less thermal degradation, less thermalhistory, and less contamination than chewing gum produced usingconventional batch mixing processes that require longer manufacturingtimes and more manufacturing steps.

A still further feature and advantage of the present invention is toprovide an automated continuous system and method for producing chewinggum that substantially reduces waste material.

Yet another feature and advantage of the present invention is to providean automated continuous system and method that reduces both errors andvariability in manufacturing.

The foregoing and other features and advantages of the invention willbecome further apparent from the following detailed description of thepresently preferred embodiments, read in conjunction with theaccompanying examples and drawings. The detailed description, examplesand drawings are intended to be merely illustrative rather thanlimiting, the scope of the invention being defined by the appendedclaims and equivalents thereof.

Additional features and advantages of the present invention aredescribed in, and will be apparent from, the detailed description of thepresently preferred embodiments and from the drawings

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial exploded perspective view of a preferred Buss highefficiency mixer used to practice the method of the invention,illustrating a mixing barrel and mixing screw arrangement.

FIG. 2A is a perspective view of an on-screw element used on theupstream side of a restriction ring assembly, in the presently preferredhigh efficiency mixer configuration.

FIG. 2B is a perspective view of an on-screw element used on thedownstream side of the restriction ring assembly in the presentlypreferred high efficiency mixer configuration.

FIG. 2C is a perspective view of a restriction ring assembly used in thepresently preferred high efficiency mixer configuration.

FIG. 3 is a perspective view showing the relative positioning of theelements of FIGS. 2A, 2B and 2C in the presently preferred highefficiency mixer configuration.

FIG. 4 is a perspective view of a low-shear mixing screw element used inthe presently preferred high efficiency mixer configuration.

FIG. 5 is a perspective view of a high-shear mixing screw element usedin the presently preferred high efficiency mixer configuration.

FIG. 6 is a perspective view of a barrel pin element used in thepresently preferred high efficiency mixer configuration.

FIG. 7 is a schematic diagram of a presently preferred arrangement ofmixing barrel pins and ingredient feed ports used to practice the methodof the invention.

FIG. 8 is a schematic diagram of a presently preferred mixing screwconfiguration used to practice the method of the invention.

FIG. 9 is a black box diagram of the system components of the presentinvention to perform automatic continuous production of chewing gum.

FIG. 10 is a black box diagram of the system components of the presentinvention to perform automatic continuous production of chewing gum aswell as the components necessary for automated downstream processing ofthe chewing gum subsequent to mixing.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

The present invention provides an automated control process that can beused to manage a continuous extruder mixing of base, gum or acombination of base and gum in a single extruder. Furthermore, controlof downstream operations following extrusion, such as sheeting, dusting,scoring and wrapping, is also disclosed.

The present invention is a method for the total manufacture of chewinggum, using a single continuous high-efficiency mixer, without requiringthe separate manufacture of chewing gum base. This method can beadvantageously performed using a continuous mixer whose mixing screw iscomposed primarily of precisely arranged mixing elements with only aminor fraction of simple conveying elements. A presently preferred mixeris a blade-and-pin mixer exemplified in FIG. 1. A blade-and-pin mixeruses a combination of selectively configured rotating mixer blades andstationary barrel pins to provide efficient mixing over a relativelyshort distance. A commercially available blade-and-pin mixer is the Busskneader, manufactured by Buss AG in Switzerland, and available from BussAmerica, located in Bloomingdale, Ill.

Referring to FIG. 1, a presently preferred blade-and-pin mixer 100includes a single mixing screw 120 turning inside a barrel 140 which,during use, is generally closed and completely surrounds the mixingscrew 120. The mixing screw 120 includes a generally cylindrical shaft122 and three rows of mixing blades 124 arranged at evenly spacedlocations around the screw shaft 122 (with only two of the rows beingvisible in FIG. 1). The mixing blades 124 protrude radially outward fromthe shaft 122, with each one resembling the blade of an axe.

The mixing barrel 140 includes an inner barrel housing 142 which isgenerally cylindrical when the barrel 140 is closed around the screw 120during operation of the mixer 100. Three rows of stationary pins 144 arearranged at evenly spaced locations around the screw shaft 142, andprotrude radially inward from the barrel housing 142. The pins 144 aregenerally cylindrical in shape, and may have rounded or bevelled ends146.

The mixing screw 120 with blades 124 rotates inside the barrel 140 andis driven by a variable speed motor (not shown). During rotation, themixing screw 120 also moves back and forth in an axial direction,creating a combination of rotational and axial mixing which is highlyefficient. During mixing, the mixing blades 124 continually pass betweenthe stationary pins 144, yet the blades and the pins never touch eachother. Also, the radial edges 126 of the blades 124 never touch thebarrel inner surface 142, and the ends 146 of the pins 144 never touchthe mixing screw shaft 122.

FIGS. 2A-2C and 3-6 illustrate various screw elements which can be usedto configure the mixing screw 120 for optimum use. FIGS. 2A and 2Billustrate on-screw elements 20 and 21 which are used in conjunctionwith a restriction ring assembly. The on-screw elements 20 and 21 eachinclude a cylindrical outer surface 22, a plurality of blades 24projecting outward from the surface 22, and an inner opening 26 with akeyway 28 for receiving and engaging a mixing screw shaft (not shown).The second on-screw element 21 is about twice as long as the firston-screw element 20.

FIG. 2C illustrates a restriction ring assembly 30 used to build backpressure at selected locations along the mixing screw 120. Therestriction ring assembly 30 includes two halves 37 and 39 mounted tothe barrel housing 142, which halves engage during use to form a closedring. The restriction ring assembly 30 includes a circular outer rim 32,an inner ring 34 angled as shown, and an opening 36 in the inner ringwhich receives, but does not touch, the on-screw elements 20 and 21mounted to the screw shaft. Mounting openings 35 in the surface 32 ofboth halves of the restriction ring assembly 30 are used to mount thehalves to the barrel housing 142.

FIG. 3 illustrates the relationship between the restriction ringassembly 30 and the on-screw elements 20 and 21 during operation. Whenthe mixing screw 120 is turning inside the barrel 140, and reciprocatingaxially, the clearances between the on-screw elements 20 and 21 and theinner ring 34 provide the primary means of passage of material from oneside of the restriction ring assembly 30 to the other. The on-screwelement 20 on the upstream side of the restriction ring assemblyincludes a modified blade 27 permitting clearance of the inner ring 34.The other on-screw element 21 is placed generally downstream of therestriction ring assembly 30, and has an end blade (not visible) whichmoves close to and wipes the opposite surface of the inner ring 34.

The clearances between outer surfaces 22 of the on-screw elements 20 and21 and the inner ring 34 of the restriction ring assembly 30, which canvary and preferably are on the order of 1-5 mm, determine to a largeextent how much pressure build-up will occur in the upstream region ofthe restriction ring assembly 30 during operation of the mixer 100. Itshould be noted that the upstream on-screw element 20 has an L/D ofabout 1/3, and the downstream on-screw element 21 has an L/D of about2/3, resulting in a total L/D of about 1.0 for the on-screw elements.The restriction ring assembly 30 has a smaller L/D of about 0.45 whichcoincides with the L/D of the on-screw elements 20 and 21, which engageeach other but do not touch the restriction ring assembly.

FIGS. 4 and 5 illustrate the mixing or "kneading" elements which performmost of the mixing work. The primary difference between the lower shearmixing element 40 of FIG. 4 and the higher shear mixing element 50 ofFIG. 5 is the size of the mixing blades which project outward on themixing elements. In FIG. 5, the higher shear mixing blades 54 whichproject outward from the surface 52 are larger and thicker than thelower shear mixing blades 44 projecting outward from the surface 42 inFIG. 4. For each of the mixing elements 40 and 50, the mixing blades arearranged in three circumferentially-spaced rows, as explained above withrespect to FIG. 1. The use of thicker mixing blades 54 in FIG. 5 meansthat there is less axial distance between the blades and also lessclearance between the blades 54 and the stationary pins 144 as the screw120 rotates and reciprocates axially (FIG. 1). This reduction inclearance causes inherently higher shear in the vicinity of the mixingelements 50.

FIG. 6 illustrates a single stationary pin 144 detached from the barrel140. The pin 144 includes a threaded base 145 which permits attachmentat selected locations along the inner barrel shaft 142. It is alsopossible to configure some of the pins 144 as liquid injection ports byproviding them with hollow center openings.

FIG. 7 is a schematic view showing the presently preferred barrelconfiguration, including the presently preferred arrangement of barrelpins 144. FIG. 8 is a corresponding schematic view illustrating thepresently preferred mixing screw configuration. The mixer 200 whosepreferred configuration is illustrated in FIGS. 7 and 8 has an overallactive mixing L/D of about 19.

The mixer 200 includes an initial feed zone 210 and five mixing zones220, 230, 240, 250 and 260. The zones 210, 230, 240, 250 and 260 includefive possible large feed ports 212, 232, 242, 252 and 262, respectively,which can be used to add major (e.g. solid) ingredients to the mixer200. The zones 240 and 260 are also configured with five smaller liquidinjection ports 241, 243, 261, 263 and 264 which are used to add liquidingredients. The liquid injection ports 241, 243, 261, 263 and 264include special barrel pins 144 formed with hollow centers, as explainedabove.

Referring to FIG. 7, barrel pins 144 are preferably present in most orall of the available locations, in all three rows as shown.

Referring to FIG. 8, the presently preferred configuration of the mixingscrew 120 for most chewing gum products is schematically illustrated asfollows. Zone 210, which is the initial feed zone, is configured withabout 11/3 L/D of low shear elements, such as the element 40 shown inFIG. 4. The L/D of the initial feed zone 210 is not counted as part ofthe overall active mixing L/D of 19, discussed above, because itspurpose is merely to convey ingredients into the mixing zones.

The first mixing zone 220 is configured, from left to right (FIG. 8),with two low shear mixing elements 40 (FIG. 4) followed by two highshear elements 50 (FIG. 5). The two low shear mixing elements contributeabout 11/3 L/D of mixing, and the two high shear mixing elementscontribute about 11/3 L/D of mixing. Zone 220 has a total mixing L/D ofabout 3.0, including the end part covered by a 57 mm restriction ringassembly 30 with cooperating on-screw elements 20 and 21 (not separatelydesignated in FIG. 8).

The restriction ring assembly 30 with cooperating on-screw elements 20and 21, straddling the end of the first mixing zone 220 and the start ofthe second mixing zone 230, have a combined L/D of about 1.0, part ofwhich is in the second mixing zone 230. Then, zone 230 is configured,from left to right, with three low shear mixing elements 40 and 1.5 highshear mixing elements 50. The three low shear mixing elements contributeabout 2.0 L/D of mixing, and the 1.5 high shear mixing elementscontribute about 1.0 L/D of mixing. Zone 230 has a total mixing L/D ofabout 4.0.

Straddling the end of the second mixing zone 230 and the start of thethird mixing zone 240 is a 60 mm restriction ring assembly 30 withcooperating on-screw elements 20 and 21 having an L/D of about 1.0.Then, zone 240 is configured, from left to right, with 4.5 high shearmixing elements 50 contributing a mixing L/D of about 3.0. Zone 240 alsohas a total mixing L/D of about 4.0.

Straddling the end of the third mixing zone 240 and the start of thefourth mixing zone 250 is another 60 mm restriction ring assembly 30with cooperating on-screw elements having an L/D of about 1.0. Then, theremainder of the fourth mixing zone 250 and the fifth mixing zone 260are configured with eleven low shear mixing elements 40 contributing amixing L/D of about 71/3. Zone 250 has a total mixing L/D of about 4.0,and zone 260 has a total mixing L/D of about 4.0.

Before explaining where the various chewing gum ingredients are added tothe continuous mixer 200, and how they are mixed, it is helpful todiscuss the composition of typical chewing gums that can be made usingthe method of the invention. A chewing gum generally includes a watersoluble bulk portion, a water insoluble chewing gum base portion, andone or more flavoring agents. The water soluble portion dissipates overa period of time during chewing. The gum base portion is retained in themouth throughout the chewing process.

The insoluble gum base generally includes elastomers, elastomerplasticizers (resins), fats, oils, waxes, softeners and inorganicfillers. The elastomers may include polyisobutylene,isobutylene-isoprene copolymer, styrene butadiene copolymer and naturallatexes such as chicle. The resins may include polyvinyl acetate andterpene resins. Low molecular weight polyvinyl acetate is a preferredresin. Fats and oils may include animal fats such as lard and tallow,vegetable oils such as soybean and cottonseed oils, hydrogenated andpartially hydrogenated vegetable oils, and cocoa butter. Commonly usedwaxes include petroleum waxes such as paraffin and microcrystalline wax,natural waxes such as beeswax, candellia, carnauba and polyethylene wax.

The gum base typically also includes a filler component such as calciumcarbonate, magnesium carbonate, talc, dicalcium phosphate and the like;softeners, including glycerol monostearate and glycerol triacetate; andoptional ingredients such as antioxidants, color and emulsifiers. Thegum base constitutes between 5-95% by weight of the chewing gumcomposition, more typically 10-50% by weight of the chewing gum, andmost commonly 20-30% by weight of the chewing gum.

The water soluble portion of the chewing gum may include softeners, bulksweeteners, high intensity sweeteners, flavoring agents and combinationsthereof. Softeners are added to the chewing gum in order to optimize thechewability and mouth feel of the gum. The softeners, which are alsoknown as plasticizers or plasticizing agents, generally constitutebetween about 0.5-15% by weight of the chewing gum. The softeners mayinclude glycerin, lecithin, and combinations thereof. Aqueous sweetenersolutions such as those containing sorbitol, hydrogenated starchhydrolysates, corn syrup and combinations thereof, may also be used assofteners and binding agents in chewing gum.

Bulk sweeteners constitute between 5-95% by weight of the chewing gum,more typically 20-80% by weight of the chewing gum and most commonly30-60% by weight of the chewing gum. Bulk sweeteners may include bothsugar and sugarless sweeteners and components. Sugar sweeteners mayinclude saccharide containing components including but not limited tosucrose, dextrose, maltose, dextrin, dried invert sugar, fructose,levulose, galactose, corn syrup solids, and the like, alone or incombination. Sugarless sweeteners include components with sweeteningcharacteristics but are devoid of the commonly known sugars. Sugarlesssweeteners include but are not limited to sugar alcohols such assorbitol, mannitol, xylitol, hydrogenated starch hydrolysates, maltitol,and the like, alone or in combination.

High intensity sweeteners may also be present and are commonly used withsugarless sweeteners. When used, high intensity sweeteners typicallyconstitute between 0.001-5% by weight of the chewing gum, preferablybetween 0.01-1% by weight of the chewing gum. Typically, high intensitysweeteners are at least 20 times sweeter than sucrose. These may includebut are not limited to sucralose, aspartame, salts of acesulfame,alitame, saccharin and its salts, cyclamic acid and its salts,glycyrrhizin, dihydrochalcones, thaumatin, monellin, and the like, aloneor in combination.

Combinations of sugar and/or sugarless sweeteners may be used in chewinggum. The sweetener may also function in the chewing gum in whole or inpart as a water soluble bulking agent. Additionally, the softener mayprovide additional sweetness such as with aqueous sugar or alditolsolutions.

Flavor should generally be present in the chewing gum in an amountwithin the range of about 0.1-15% by weight of the chewing gum,preferably between about 0.2-5% by weight of the chewing gum, mostpreferably between about 0.5-3% by weight of the chewing gum. Flavoringagents may include essential oils, synthetic flavors or mixtures thereofincluding but not limited to oils derived from plants and fruits such ascitrus oils, fruit essences, peppermint oil, spearmint oil, other mintoils, clove oil, oil of wintergreen, anise and the like. Artificialflavoring agents and components may also be used in the flavoringredient of the invention. Natural and artificial flavoring agents maybe combined in any sensorially acceptable fashion.

Optional ingredients such as colors, emulsifiers, pharmaceutical agentsand additional flavoring agents may also be included in chewing gum.

In accordance with one embodiment of the invention, the gum base andultimate chewing gum product are made continuously in the same mixer.Generally, the gum base portion is made using a mixing L/D of about 25or less, preferably about 20 or less, most preferably about 15 or less.Then, the remaining chewing gum ingredients are combined with the gumbase to make a chewing gum product using a mixing L/D of about 15 orless, preferably about 10 or less, most preferably about 5 or less. Themixing of the gum base ingredients and the remaining chewing gumingredients may occur in different parts of the same mixer or mayoverlap, so long as the total mixing is achieved using an L/D of about40 or less, preferably about 30 or less, most preferably about 20 orless.

When the preferred blade-and-pin mixer is used, having the preferredconfiguration described above, the total chewing gum can be made using amixing L/D of about 19. The gum base can be made using an L/D of about15 or less, and the remaining gum ingredients can be combined with thegum base using a further L/D of about 5 or less.

In order to accomplish the total chewing gum manufacture using thepreferred blade-and-pin mixer 200, it is advantageous to maintain therpm of the mixing screw 120 at less than about 150, preferably less thanabout 100. Also, the mixer temperature is preferably optimized so thatthe gum base is at about 130° F. or lower when it initially meets theother chewing gum ingredients, and the chewing gum product is at about130° F. or lower (preferably 125° F. or lower) when it exits the mixer.This temperature optimization can be accomplished, in part, byselectively heating and/or water cooling the barrel sections surroundingthe mixing zones 220, 230, 240, 250 and 260.

In order to manufacture the gum base, the following preferred procedurecan be followed. The elastomer, filler, and at least some of theelastomer solvent are added to the first large feed port 212 in the feedzone 210 of the mixer 200, and are subjected to highly dispersive mixingin the first mixing zone 220 while being conveyed in the direction ofthe arrow 122. The remaining elastomer solvent (if any) andpolyvinylacetate are added to the second large feed port 232 in thesecond mixing zone 230, and the ingredients are subjected to a moredistributive mixing in the remainder of the mixing zone 230.

Fats, oils, waxes (if used), emulsifiers and, optionally, colors andantioxidants, are added to the liquid injection ports 241 and 243 in thethird mixing zone 240, and the ingredients are subjected to distributivemixing in the mixing zone 240 while being conveyed in the direction ofthe arrow 122. At this point, the gum base manufacture should becomplete, and the gum base should leave the third mixing zone 240 as asubstantially homogeneous, lump-free compound with a uniform color.

The fourth mixing zone 250 is used primarily to cool the gum base,although minor ingredient addition may be accomplished. Then, tomanufacture the final chewing gum product, glycerin, corn syrup, otherbulk sugar sweeteners, high intensity sweeteners, and flavors can beadded to the fifth mixing zone 260, and the ingredients are subjected todistributive mixing. If the gum product is to be sugarless, hydrogenatedstarch hydrolyzate or sorbitol solution can be substituted for the cornsyrup and powdered alditols can be substituted for the sugars.

Preferably, glycerin is added to the first liquid injection port 261 inthe fifth mixing zone 260. Solid ingredients (bulk sweeteners,encapsulated high intensity sweeteners, etc.) are added to the largefeed port 262. Syrups (corn syrup, hydrogenated starch hydrolyzate,sorbitol solution, etc.) are added to the next liquid injection port263, and flavors are added to the final liquid injection port 264.Flavors can alternatively be added at ports 261 and 263 in order to helpplasticize the gum base, thereby reducing the temperature and torque onthe screw. This may permit running of the mixer at higher rpm andthroughput.

The gum ingredients are compounded to a homogeneous mass which isdischarged from the mixer as a continuous stream or "rope". Thecontinuous stream or rope can be deposited onto a moving conveyor andcarried to a forming station, where the gum is shaped into the desiredform such as by pressing it into sheets, scoring, and cutting intosticks. Because the entire gum manufacturing process is integrated intoa single continuous mixer, there is less variation in the product, andthe product is cleaner and more stable due to its simplified mechanicaland thermal histories.

A wide range of changes and modifications to the preferred embodimentsof the invention will be apparent to persons skilled in the art. Theabove preferred embodiments, and the examples which follow, are merelyillustrative of the invention and should not be construed as imposinglimitations on the invention. For instance, different continuous mixingequipment and different mixer configurations can be used withoutdeparting from the invention as long as the preparation of a chewing gumbase and chewing gum product are accomplished in a single continuousmixer using a mixing L/D of not more than about 40.

EXAMPLE 1

Testing The Suitability Of A Continuous Mixer

The following preliminary test can be employed to determine whether aparticular continuous mixer with a particular configuration meets therequirements of a high efficiency mixer suitable for practicing themethod of the invention.

A dry blend of 35.7% butyl rubber (98.5% isobutylene-1.5% isoprenecopolymer, with a molecular weight of 120,000-150,000, manufactured byPolysar, Ltd. of Sarnia, Ontario, Canada as POLYSAR Butyl 101-3); 35.7%calcium carbonate (VICRON 15--15 from Pfizer, Inc., New York, N.Y.);14.3% polyterpene resin (ZONAREZ 90 from Arizona Chemical Company ofPanama City, Fla.) and 14.3% of a second polyterpene resin (ZONAREZ 7125from Arizona Chemical Company) is fed into the continuous mixer inquestion equipped with the mixer configuration to be tested. Thetemperature profile is optimized for the best mixing, subject to therestriction that the exit temperature of the mixture does not exceed170° C. (and preferably remains below 160° C.) to prevent thermaldegradation. In order to qualify as a suitable high efficiency mixer,the mixer should produce a substantially homogeneous, lump-free compoundwith a uniform milky color in not more than about 10 L/D, preferably notmore than about 7 L/D, most preferably not more than about 5 L/D.

To thoroughly check for lumps, the finished rubber compound may bestretched and observed visually, or compressed in a hydraulic press andobserved, or melted on a hot plate, or made into a finished gum basewhich is then tested for lumps using conventional methods.

Also, the mixer must have sufficient length to complete the manufactureof the gum base, and of the chewing gum product, in a single mixer,using a total mixing L/D of not more than about 40. Any mixer whichmeets these requirements falls within the definition of ahigh-efficiency mixer suitable for practicing the method of theinvention.

EXAMPLES 2-6

Continuous Chewing Gum Manufacture

The following examples were run using a Buss kneader with a 100 mm mixerscrew diameter, configured in the preferred manner described above(unless indicated otherwise), with five mixing zones, a total mixing L/Dof 19, and an initial conveying L/D of 11/3. No die was used at the endof the mixer, unless indicated otherwise, and the product mixture exitedas a continuous rope. Each example was designed with feed rates to yieldchewing gum product at the rate of 300 pounds per hour.

Liquid ingredients were fed using volumetric pumps into the large feedports and/or smaller liquid injection ports generally positioned asdescribed above, unless otherwise indicated. The pumps wereappropriately sized and adjusted to achieve the desired feed rates.

Dry ingredients were added using gravimetric screw feeders into thelarge addition ports positioned as described above. Again, the feederswere appropriately sized and adjusted to achieve the desired feed rates.

Temperature control was accomplished by circulating fluids throughjackets surrounding each mixing barrel zone and inside the mixing screw.Water cooling was used where temperatures did not exceed 200° F., andoil cooling was used at higher temperatures. Where water cooling wasdesired, tap water (typically at about 57° F.) was used withoutadditional chilling.

Temperatures were recorded for both the fluid and the ingredientmixture. Fluid temperatures were set for each barrel mixing zone(corresponding to zones 220, 230, 240, 250 and 260 in FIGS. 7 and 8),and are reported below as Z1, Z2, Z3, Z4 and Z5, respectively. Fluidtemperatures were also set for the mixing screw 120, and are reportedbelow as S1.

Actual mixture temperatures were recorded near the downstream end ofmixing zones 220, 230, 240 and 250; near the middle of mixing zone 260;and near the end of mixing zone 260. These mixture temperatures arereported below as T1, T2, T3, T4, T5 and T6, respectively. Actualmixture temperatures are influenced by the temperatures of thecirculating fluid, the heat exchange properties of the mixture andsurrounding barrel, and the mechanical heating from the mixing process,and often differ from the set temperatures due to the additionalfactors.

All ingredients were added to the continuous mixer at ambienttemperature (about 77° F.) unless otherwise noted.

EXAMPLE 2

This example illustrates the preparation of a sugar chunk bubble gum.For this example, the mixer configuration was varied slightly from thepreferred configuration described above and used for Examples 2-6.Specifically, a round-hole 30 mm die was installed at the exit end ofthe mixer.

A blend of 68.9% high molecular weight polyvinyl acetate and 31.1%ground talc was added into the first large feed port 212 (FIG. 7), at35.4 lb/hr.

Polyisobutylene (preheated to 100° C.) was also added to port 212 at3.95 lb/hr. Further downstream, in the first mixing zone 220, acetylatedmonoglyceride was injected at 2.6 lb/hr, using a liquid injection(hollow barrel pin) port not shown in FIG. 7.

Additional polyisobutylene (100° C.) at 3.95 lb/hr, and glycerol esterof partially hydrogenated wood rosin at 13.4 lb/hr, were added into thesecond large port 232. A mixture of 43.6% glycerol monostearate, 55.9%triacetin and 0.5% BHT was added at 6.7 lb/hr into the liquid injectionport 241.

Glycerin was injected at 2.1 lb/hr into the liquid injection port 261. Amixture of 98.4% sucrose and 1.6% citric acid was added at 170.4 lb/hrinto the large port 262. Corn syrup (40° C.) was injected at 58.5 lb/hrinto liquid injection port 263, and a mixture of 60% lemon-lime flavorand 40% soy lecithin was added at 3.0 lb/hr into the liquid injectionport 264.

The zone temperatures (Z1-Z5, °F.) were ultimately set at 440, 440, 160,61 and 61, respectively. The screw temperature (S1) was ultimately setat 80° F. The mixture temperatures (T1-T6, °F.) were ultimately measuredas 189, 176, 161, 97, 108 and 112, respectively. The screw rotation was55 rpm.

At first, the product exited the extruder at 140° F. and exhibited signsof heat stress. The zone temperatures Z1 and Z2 were then reduced by 10°F. each, and the screw temperature S1 was raised by 20° F., to thevalues shown above. This caused the chewing gum exit temperature to dropto 122° F., and the product quality improved markedly.

During chewing, the product exhibited excellent texture, flavor, andbubble blowing characteristics. No rubber lumps were visible.

EXAMPLE 3

This example illustrates the preparation of a spearmint flavoredsugarless gum. A mixture of 42.1% fine ground calcium carbonate, 18.9%glycerol ester of wood rosin, 16.7% glycerol ester of partiallyhydrogenated wood rosin, 17.0% ground butyl rubber, and 5.3% dustedground (25:75) styrene butadiene rubber (75% rubber, 25% calciumcarbonate) was added into port 212 (FIG. 7) at 38.4 lb/hr.

Low molecular weight polyvinyl acetate at 12.7 lb/hr, andpolyisobutylene (preheated to 100° C.) at 7.6 lb/hr, were added intoport 232.

A fat mixture (82° C.) was injected 50/50 into ports 241 and 243, at atotal rate of 20.9 lb/hr. The fat mixture included 35.7% hydrogenatedcottonseed oil, 30.7% hydrogenated soybean oil, 20.6% partiallyhydrogenated soybean oil, 12.8% glycerol monostearate and 0.2% BHT.

Unlike the previous examples, glycerin was injected at 25.5 lb/hr intothe fourth mixing zone 250 (FIG. 7) through a liquid injection port (notshown). A coevaporated blend of hydrogenated starch hydrolysate andglycerin (at 40° C.) was injected further downstream in the fourthmixing zone 250 through another liquid injection port (not shown). Thecoevaporated blend included 67.5% hydrogenated starch hydrolysatesolids, 25% glycerin and 7.5% water.

A mixture of 84.8% sorbitol, 14.8% mannitol and 0.4% encapsulatedaspartame was added into port 262 in the fifth mixing zone 260, at 162.3lb/hr. A mixture of 94.1% spearmint flavor and 5.9% lecithin wasinjected at 5.1 lb/hr into the port 264 located further downstream.

The zone temperatures (Z1-Z5, °F.) were set at 400, 400, 150, 62 and 62,respectively. The screw temperature (S1) was set at 66° F. The mixturetemperatures (T1-T6, ° F.) were measured as 307, 271, 202, 118, 103 and116. The mixing screw rotation was 69 rpm.

The chewing gum product exited the mixer at 117° F. The gum had goodappearance with no sorbitol spots or rubber lumps. The gum was slightlywet to the touch, sticky and fluffy (low density), but was acceptable.During chewing, the gum was considered soft initially but firmed up withcontinued chewing.

EXAMPLE 4

This example illustrates the preparation of a sugarless spearmint gumfor use in coated pellets. A mixture of 28.6% dusted ground butyl rubber(75% rubber, 25% calcium carbonate), 27.4% high molecular weight terpeneresin, 26.9% low molecular weight terpene resin and 17.1% calciumcarbonate was added into port 212 (FIG. 7) at 41.9 lb/hr.

Low molecular weight polyvinyl acetate at 24.7 lb/hr, andpolyisobutylene (preheated to 100° C.) at 1.7 lb/hr, were added intoport 232.

A fat composition (82° C.) was injected 50/50 into ports 241 and 243 ata total rate of 21.7 lb/hr. The fat composition included 22.6%hydrogenated cottonseed oil, 21.0% hydrogenated soybean oil, 21.0%partially hydrogenated soybean oil, 19.9% glycerol monostearate, 15.4%glycerin and 0.2% BHT.

A 70% sorbitol solution was injected into the fourth mixing zone 250(FIG. 7) at 17.4 lb/hr, using a hollow barrel pin liquid injection port(not shown).

A mixture of 65.8% sorbitol, 17.9% precipitated calcium carbonate and16.3% mannitol was added at 184.2 lb/hr into the final large port 262. Amixture of 71.4% spearmint flavor and 28.6% soy lecithin was added at8.4 lb/hr into the final liquid injection port 264.

The zone temperatures (Z1-Z5, °F.) were set at 400, 400, 150, 61 and 61,respectively. The screw temperature (S1) was set at 65° F. The mixturetemperatures (T1-T6,°F.) were measured as 315, 280, 183, 104, 109 and116, respectively. The screw rotation was set at 61 rpm.

The chewing gum exited the mixer at 127° F. The product appearance wasgood with no sorbitol spots or rubber lumps. However, the initial chewwas reported as being rough and grainy.

EXAMPLE 5

This example illustrates the preparation of a peppermint flavored sugarchewing gum. A mixture of 27.4% dusted ground butyl rubber (75% butylrubber dusted with 25% calcium carbonate), 14.1% lower softening terpeneresin (softening point=85° C.), 14.4% higher softening terpene resin(softening point=125° C.) and 44.1% calcium carbonate was fed at 24.6lb/hr into the first large feed port (port 212 in FIGS. 7 and 8).

A mixture of 73.5% low molecular weight polyvinyl acetate, 9.2% highmolecular weight polyvinyl acetate, 8.6 lower softening terpene resinand 8.7% higher softening terpene resin was fed at 17.4 lb/hr into thesecond large feed port 232. Polyisobutylene was also added at 3.5 lb/hrinto this port.

A fat mixture, preheated to 83° C., was injected into the liquidinjection ports in the third mixing zone (ports 241 and 243 in FIG. 7),at a total rate of 14.5 lb/hr, with 50% of the mixture being fed througheach port. The fat mixture included 0.2% BHT, 2.5% cocoa powder, 31.9%hydrogenated cottonseed oil, 19.8% glycerol monostearate, 18.7%hydrogenated soybean oil, 13.7% lecithin, and 13.2% partiallyhydrogenated cottonseed oil.

A mixture of 84.6% sugar and 15.4% dextrose monohydrate was injected at203.1 lb/hr into the large feed port 262 in the fifth mixing zone.Glycerin was added at 3.9 lb/hr into the first liquid injection port 261in the fifth mixing zone. Corn syrup, preheated to 44° C., was added at30.0 lb/hr into the second liquid injection port 263 in the fifth mixingzone. A mixture of 90.0% peppermint flavor and 10.0% lecithin wasinjected into the third liquid injection port 264 in the fifth mixingzone at 3.0 lb/hr.

The zone temperatures Z1-Z5 were set (in °F.) at 350, 350, 110, 25 and25, respectively. The mixing screw temperature S1 was set at 101° F. Themixer temperatures T1-T6 were measured at steady state (in °F.) as 320,280, 164, 122, 105 and 103, respectively. The screw rotation was 63 rpm,and the product exited the mixer at 52°-53° C.

The peppermint sugar gum product was desirably soft, and acceptable inquality.

EXAMPLE 6

This example illustrates the preparation of a sugarless stick bubblegum. For this example, the screw configuration shown in FIG. 8, and usedfor the previous examples, was varied as follows. The conveying section210 and mixing sections 220, 250 and 260 were configured substantiallyas before. In the second mixing zone 230, the three low shear elements40 were also not changed.

Thereafter, the 11/2 high shear elements 50 in zone 230, the restrictionelement 30 overlapping zones 230 and 240, all of zone 240, and therestriction element 30 overlapping zones 240 and 250 were removed. Threehigh shear elements 50 (combined L/D=2.0) were placed in zone 230 andextended into zone 240. Two and one-half low shear elements 40 (combinedL/D=12/3) followed in zone 240. Then, three and one-half high shearelements 50 (combined L/D=21/3) followed in zone 240 and extended intozone 250. The eleven low-shear elements 40 in zones 250 and 260 were notchanged.

To make the product, a mixture of 53.3% high molecular weight polyvinylacetate, 31.0% talc, 12.2% glycerol ester of wood rosin and 3.5% dustedground (25:75) styrene-butadiene rubber (75% rubber, 25% calciumcarbonate) were fed into the large port 212 (FIG. 7) at 54.9 lb/hr.Polyisobutylene (preheated to 100° C.) was pumped into the same port at9.0 lb/hr.

Glycerol ester of partially hydrogenated wood rosin at 15.3 lb/hr, andtriacetin at 4.4 lb/hr, were added into the large port 232 in the secondmixing zone 230.

A fat/wax mixture (at 82° C.) was fed 50/50 into the liquid injectionports 241 and 243 in the third mixing zone 240, at a total rate of 13.9lb/hr. The mixture included 50.3% glycerol monostearate, 49.4% paraffin(m.p.=135° F.) and 0.3% BHT.

Diluted glycerin was injected into the fourth mixing zone 250 at 28.2lb/hr using a liquid injection port (not shown). The dilution was 87%glycerin and 13% water.

A mixture of 84.0% sorbitol, 12.7% mannitol, 1.1% fumaric acid, 0.2%aspartame, 0.4% encapsulated aspartame, 0.7% adipic acid and 0.9% citricacid was fed into port 262 in the fifth mixing zone 260 at 165.0 lb/hr.A mixture of 51.6% bubble gum flavor and 48.4% soy lecithin was injectedinto port 264 in zone 260 at 9.3 lb/hr.

The zone temperatures (Z1-Z5, °F.) were set at 350, 350, 100, 64 and 64,respectively. The screw temperature (S1) was set at 100° F. The mixturetemperatures (T1-T6, °F.) were recorded as 286, 260, 163, 107, 104 and112, respectively. The screw rotation was 75 rpm.

The chewing gum exited the mixer at 118° F. The finished product lookedgood and contained no base lumps. The flavor and texture were very goodduring chewing, as were the bubble blowing characteristics.

Referring now to FIGS. 9 and 10, an embodiment of the system 301 of thepresent invention is generally illustrated in the form of an automatedprocess control system 301. The process control system 301 includes anumber of components including an operator interface computer 310capable of being controlled by, for example, a human operator 312 or,alternatively, a memory storage device 314. To this end, the operatorinterface computer 310 receives process control parameters from theoperator 312 and/or the memory storage device 314. The process controlparameters are sent to a programmable controller 316. As an example ofprocess control parameters, ingredients percentages may be entered intothe operator interface computer 310 and converted into, for example,feeder rate set points. Alternatively, feeder rate set points may bedirectly entered by the operator 312. The operator interface computer310 further receives real time operation data from the programmablecontroller 316 and may provide data to the operator 312 via a graphicalinterface (not shown). The operator interface computer 310 may furtherstore data and process parameters in the memory storage device 314.Printed or on-line reports of current or archival run information to theoperator 312 may further be provided on a display 315 and/or sent to aprinter. This may be implemented by those skilled in the art.

As illustrated, the programmable controller 316 receives formula andprocess parameters from the operator interface computer 310. Theprogrammable controller 316 is capable of performing control algorithmsand logical operations and transmits real-time instructions to devicecontrollers to be described hereinafter. Further, the programmablecontroller 316 may receive real-time data from the device controllersand relay the real-time data to the operator interface computer 310.Alternatively, devices may be directly controlled by the programmablecontroller 316. Such devices include, but are not limited to, ingredientfeed agitators, heaters, hopper refillers, and the like. In anembodiment, control functions handled by dedicated controllers, e.g.,ingredient feed rate control, may alternatively be handled by theprogrammable controller 316. Further, the programmable controller 316may provide inventory and order data to maintain supplies of ingredientsat optimum levels.

One such device controller referenced above includes an extruder heatingand cooling controller 318. The extruder heat/cool controller 318receives both start and stop instructions and extruder zone temperatureparameters from the programmable controller 316. Further, real-timetemperature data is received from extruder heating and cooling devices320 using sensors 321 known in the art. The extruder heat/coolcontroller 318 turns the extruder heat/cool devices 320 on and offand/or modulates them to maintain actual temperatures within rangesspecified and input via the process control parameters. Further, theextruder heat/cool controller 318 relays actual temperature data to theprogrammable controller 316.

Another device controller used in the system of the present invention isan extruder controller 322. The extruder controller 322 receives startand stop instructions as well as parameters, such as revolutions perminute, from the programmable controller 316. Further, the extrudercontroller 322 may receive at least real-time material temperatures,rpm, torque, and power data from an extruder 324. An extruder motor (notshown) of the extruder 324 is controlled by the extruder controller 322to maintain the speed at an rpm specified by the process parameters. Theextruder controller 322 may further relay operation data includingtemperatures from the extruder 324 to the programmable controller 316.

Yet another device controller used in the system of the presentinvention is an ingredient feeder controller 326. The ingredient feedercontroller 326 receives start and stop instructions and ingredient feedrates from the programmable controller 316. Further, real-time weightsand rpm data are received by the ingredient feeder controller 326 fromingredient feeders 328. As a result, the ingredient feeder controller326 calculates actual feed rates and controls feeder speed to maintainfeed rates within specified ranges. Compensation for erratic weightchanges during hopper refill events may also be controlled by theingredient feeder controller 326. Further, the ingredient feedercontroller 326 allows for relay of data from the feeders 328 to theprogrammable controller 316. The types of ingredients that may be fedinclude those required for producing a completed chewing gum, finishedchewing gum base, gum only and/or gum base ingredients.

The process control system 301 of the present invention also includes aplurality of controlled devices. A first such device is the memorystorage device 314 which provides for non-volatile storage of digitalinformation, such as, for example, on a disk or a tape.

Other controlled devices include the extruder heat/cool devices 320which heat or cool a multiplicity of zones on the extruder 324.Typically, cooling may be performed by circulating fluid through ajacket surrounding a barrel of the extruder 324. Heating, on the otherhand, may be accomplished by electric heaters placed on walls of theextruder 324. Preferably, however, circulating a heated fluid through ajacket surrounding a barrel of the extruder 324 is implemented toconduct heating of the extruder 324.

The extruder 324 also includes one or more screw shafts that arerotated. Alternatively, the extruder 324 may be imparted with axialmotion and rotation such as described above with reference to FIGS. 1-8.The shafts are rotated by a motor and an associated drive train.Temperature sensors 338 may be provided projecting inward from a barrelwall to measure temperature of products at selected points along thelength of the extruder 324.

The ingredient feeders 328 of the system 301 of the present inventionmay include feeding of both liquid and dry material by gravimetricfeeders which transfer ingredients into the extruder 324. The feeding isaccomplished by a variable speed motor that drives a pump or an auger.However, other ingredient feeders are contemplated and known in the artsuch as vibrating pans or trays, rotary valves, mass flow meters orvariable aperture discharge valves. Such feeders may be implemented bythose skilled in the art. A scaling system or sensors 340 may beimplemented to weigh the ingredient feeders and its contents; thisinformation is then used by the ingredient feeder controller 326 tomaintain the desired feed rate. A hopper level detector 342 may also beimplemented to transmit information to the programmable controller 316for directing the refill of the hopper. Preferably, however, hopperrefill is triggered through a weight sensor associated with thegravimetric feeders. Upon detection of a drop in total weight below apreset value indicating a low hopper level, a refill device isautomatically triggered to refill the particular hopper.

Other control devices include feeder temperature control devices 330,ingredient feeder agitators 332 and an ingredient hopper refiller system334. The ingredient feed temperature control devices 330 may includevarious type of heaters and/or chillers which maintain the temperatureof hoppers, feed lines, tanks and other feeder components withinacceptable ranges and transmit actual temperatures to the programmablecontroller 316. Such variables are sensed with appropriate sensors 331in communication with the feeder temperature control devices 330 and theprogrammable controller 316. The ingredient feeder agitators 332 mayinclude stirrers and vibratory devices that prevent bridging andblocking in the feeders. Such conditions may be sensed using appropriatesensors 335 operatively connected to the agitators 334 and providing asignal to the programmable controller 316. Preferably, agitation andvibration occurs at defined intervals of time or at predetermined hopperlevels or based on other sensed conditions rather than direct sensing ofa blockage condition to activate agitation. Finally, the ingredienthopper refiller system 334 includes the capability to refill theingredient feeder hopper when directed by the programmable controller316. To this end, refill confirmation and current inventory oringredient usage status are transmitted to the programmable controller316.

Preferably, a multi-level alarm 336 is also provided in the system 301of the present invention. The alarm 336 includes a first level having amessage capability which provides indication of a failure or anout-of-specification reading of a non-critical nature. For example, thefailure of a product temperature sensor may be indicated by the messagealarm. A message may be displayed on a monitor, but no further action isnecessarily taken by the programmable controller 316. An audible warningmay also be provided in addition to the message.

A second level of warning on the alarm 336 is a warning of a failure orout-of-specification performance that is critical to continued operationof the system 301. A warning alarm may indicate an impeding criticalalarm if the problem is not corrected within a specified time interval.This time interval may vary depending on the particular system affectedand/or the degree of departure from the specified tolerance. A warningmessage may also be displayed on a monitor and/or an audible warning maybe sounded.

A third level of the alarm 336 is the critical alarm conditionindicating a failure requiring immediate shutdown of the system 301. Awarning condition that has not been corrected within an allowablepredetermined time interval may also trigger a critical alarm. Automaticshut down of the extruder 324 may be initiated and accompanied by amessage on a monitor and/or an audible warning. Override provisions maybe provided to allow the operator 312 to prevent automatic shutdown ifsuch action is appropriate.

The above description describes the process control system 301 in itsbasic form. However, two or more device controllers may be combined intoa single unit. For example, a single controller may be provided tohandle extruder motor control and extruder heat/cool control functions.Likewise, agitators and feeder temperature control functions may behandled by a separate controller rather than directly controlled by theprogrammable controller 316 as described above.

Furthermore, the operator interface computer 310 may be used as aninterface between the programmable controller 316 and one or more of thedevice controllers, such as the extruder heat/cool controller 318, theextruder controller 322 and/or the ingredient feeder controller 326.

Furthermore, a portion or all of the run data, such as actualtemperatures, actual feed rates and the like, may be stored on apermanent media for later review. This is beneficial when an end producthas been found to be defective and review of the run data may assist inidentifying the reasons for the defect. Storage of such data may beprovided on a memory storage device controlled by the operator interfacecomputer 10 or the programmable controller 316.

Furthermore, alarm conditions may be detected by device controllers andrelayed to the programmable controller 316. Alternatively, the devicecontroller may simply relay data to the programmable controller 316which then makes the determination whether an alarm condition exists.Likewise, separate distinct subsystems may be used in each arrangement.

Hopper refill has been described above as preferably being performed byautomated equipment. In some instances, however, hopper refill may bedesirably accomplished manually by directing the operator 312 via theoperator interface computer 310 of the requirement for hopper refill.Associated monitors and/or audible signals may be implemented to warnthe operator of the need for hopper refill.

The ingredient feeder controller 326 may also control volumetric devicesin addition to or in lieu of the described gravimetric feeders. Further,data from devices not required for control purposes, in addition to datathat is required for control purposes, may be relayed through one ormore device controllers to the programmable controller 316 or may besent to the programmable controller 316 directly. One example isingredient temperature measurement.

Following mixing, additional automation is performed including the stepsof sheeting and wrapping the chewing gum product. More specifically, theextruder 324 may be fitted with a die to form the gum into a slab, asheet, a rope or other desired initial shape. Alternatively, theunformed output from the mixing extruder may be transferred into asecondary forming extruder 348 which produces the initial shape. Anautomated operation may make use of inputs, such as pressure anddimension of the gum output to control extruder temperature and speed,and take away speed, for example, of a conveyor, for the output tocontrol the dimensions of the formed gum stream. Appropriate sensors 344may be implemented to sense particular parameters to control the formingextruder 348.

After leaving the forming extruder 348, the gum may be moved by atransport device, such as a conveyor, or fed directly into rollers.Prior to entering the rollers, the gum is preferably dusted with asuitable rolling compound, such as sugar or mannitol, by a duster 350.The automated control system 301 may further include optical inspectionor gravimetric inputs using appropriate sensors 352 to regulate theapplication of the rolling compound and/or the speed of the gum passingthrough an applicator device.

If the gum is to be formed into, for example, sticks or tabs, the formedand dusted product is fed into one or more sets of rollers 354 whichreduce the thickness of the gum to its desired final value. The productmay then be simultaneously or separately scored to produce the finalpiece dimensions. The automated process control system 301 may beimplemented to monitor with appropriate sensors 358 such values asdimensions and temperature of the product and uses these measurements tocontrol roller speeds, spacing, i.e., roller separation and temperature.

Finally, once the gum is formed and scored into its final shapes, asequence of wrapping operations is performed by a wrapping machine 360for covering and combining the product into units suitable for consumeruse, consumer purchase, retail display and shipping. Prior to wrapping,the scored product is divided into defined units as desired. Therefore,cutting or breaking of the scored product is performed during thewrapping as indicated in FIG. 10. The wrapping operations areautomatically and continuously controlled in various ways. For example,the rate of feed and wrapping is controlled to maximize efficiency forchanges in production speed and wrapping variables. The temperatures ofincoming gum pieces can be optimized by controlling upstream operations.Various operations of the wrapping machine 360 are made to allow forvariations in the gum product and wrapping materials detected by varioustypes of sensors 362.

As a result of the automated control process described above, laborcosts and manufacturing variability and errors are significantlyreduced. Further, manufacturing flexibility is increased, and wastematerial is reduced. Further, the efficiencies result in a moreconsistent quality of the resultant product.

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications may be madewithout departing from the spirit and scope of the present invention andwithout diminishing its attendant advantages. It is, therefore, intendedthat such changes and modifications be covered by the appended claims.

We claim:
 1. A system for automatic and continuous production of chewinggum, the system comprising:means for inputting operational parametersand storing a signal representative of each of the operationalparameters; means for automatically and continuously feeding ingredientsnecessary for continuous production of chewing gum; means for collectingand automatically and continuously mixing the ingredients; and means forcontrolling connected to the means for inputting, the means forautomatically and continuously feeding and the means for collecting andautomatically and continuously mixing wherein the means for controllingcompares the signals representative of the operational parameters andprovides a signal to the means for feeding and the means for collectingand mixing to effect feeding, collecting or mixing.
 2. The system ofclaim 1 wherein the operational parameters input include ingredientpercentages or feed rates.
 3. The system of claim 1 furthercomprising:means for monitoring ingredient temperatures and providing asignal indicative thereof to the means for controlling.
 4. The system ofclaim 1 further comprising:means for monitoring feed rate of theingredients fed by the means for automatically and continuously feedingand providing a signal indicative thereof to the means for controlling.5. The system of claim 1 further comprising:means for automatically andcontinuously forming the mixed ingredients into a predetermined shapedischarged from the means for collecting and automatically andcontinuously mixing.
 6. The system of claim 1 wherein the means forcollecting and automatically and continuously mixing the ingredientsforms the ingredients into a predetermined shape during discharge. 7.The system of claim 5 further comprising:means for automatically dustingthe predetermined shape formed in the means for automatically andcontinuously forming wherein the means for automatically dusting isconnected to and controlled by the means for controlling.
 8. The systemof claim 6 further comprising:means for automatically dusting thepredetermined shape wherein the means for automatically dusting isconnected to and controlled by the means for controlling.
 9. The systemof claim 5 further comprising:means for automatically rolling thepredetermined shape discharged from the means for automatically andcontinuously forming.
 10. The system of claim 6 further comprising:meansfor automatically rolling the predetermined shape wherein the means forautomatically rolling is connected to and controlled by the means forcontrolling.
 11. The system of claim 5 further comprising:means forautomatically scoring the predetermined shape wherein the means forautomatically scoring is connected to and controlled by the means forcontrolling.
 12. The system of claim 11 further comprising:means forautomatically wrapping the predetermined shape following division of thescored predetermined shape into defined units wherein the means forautomatically wrapping is connected to and controlled by the means forcontrolling.
 13. The system of claim 6 further comprising:means forautomatically scoring the predetermined shape wherein the means forautomatically scoring is connected to and controlled by the means forcontrolling.
 14. The system of claim 13 further comprising:means forautomatically wrapping the predetermined shape following the division ofthe scored predetermined shape into defined units wherein the means forautomatically wrapping is connected to and controlled by the means forcontrolling.
 15. The system of claim 1 wherein the ingredients are thoserequired for producing finished gum base.
 16. The system of claim 1wherein the ingredients are gum base ingredients.
 17. A system forautomatic and continuous production of chewing gum base, the systemcomprising:means for inputting operational parameters and storing asignal representative of each of the operational parameters; means forautomatically and continuously feeding ingredients necessary forcontinuous production of chewing gum base; means for collecting andautomatically and continuously mixing the ingredients; means forcontrolling connected to the means for inputting, the means forautomatically and continuously feeding and the means for collecting andautomatically and continuously mixing wherein the means for controllingcompares the signals representative of the operational parameters andprovides a signal to the means for feeding and the means for collectingand mixing to effect feeding, collecting or mixing.
 18. The system ofclaim 17 further comprising:means for monitoring feed rate of theingredients fed by the means for automatically and continuously feedingand providing a signal indicative thereof to the means for controlling.19. A system for automatic and continuous production of chewing gum, thesystem comprising:means for automatically and continuously feedingingredients necessary for continuously producing the chewing gum; meansfor continuously mixing the ingredients to form a mixture wherein theingredients are fed to the means for continuously mixing from the meansfor feeding; means for automatically and continuously discharging themixture from the means for mixing; means for automatically forming themixture into a predetermined shape wherein the means for formingreceives the mixture from the means for discharging; means forautomatically scoring the predetermined shape wherein the means forscoring receives the predetermined shape from the means for forming; andmeans for automatically wrapping the predetermined shape followingdivision into defined units wherein the means for wrapping receives thedefined units from the means for scoring.
 20. The system of claim 19further comprising:means for inputting operational parameters andstoring a signal representative of each of the operational parameters;and controller means receiving the signal representative of each of theoperational parameters and controlling the system based on theoperational parameters.
 21. The system of claim 19 furthercomprising:means for monitoring the ingredients and mixture duringfeeding and mixing.
 22. The system of claim 19 further comprising:meansfor monitoring the predetermined shape during forming, scoring andwrapping.
 23. The system of claim 19 further comprising:alarm meansproviding a signal indicative of a condition sensed during theproduction.